1. Field of the Invention
The present invention relates to a laser attachment device which facilitates adjustment of luminance distribution of a laser beam, and to an optical pick-up device using the same.
2. Description of the Related Art
As an embodiment of a conventional laser attachment device, a structure shown in FIG. 6 is known. As shown in the drawing, an optical axis adjustment mechanism part 142 is disposed on a base 141 of the laser attachment device. The optical axis adjustment mechanism part 142 is formed of a fixed seat 143 and a movable seat 144. An opening region 145 is formed in the fixed seat 143, and the inner surface of the opening region 145 is processed into a spherical surface centered at an optical axis 146 of an optical system. Meanwhile, the outer circumferential surface of the movable seat 144 is similarly processed into a spherical surface centered at the optical axis 146 of the optical system. A LD package 148 is disposed in close contact with a reference surface 147 of the movable seat 144, and the movable seat 144 is fitted into the opening region 145 of the fixed seat 143. Then, the position of the movable seat 144 is adjusted by an optical axis adjustment machine 149. Thus, the emitting direction of the laser beam emitted from the LD package 148 and the optical axis 146 of the optical system are adjusted. Displacement in luminance distribution of the laser beam on an objective lens (not shown) is also adjusted in a similar manner by the position adjustment of the movable seat 144. Note that, after the optical axis and the luminance distribution are adjusted, positional relationship between the fixed seat 143 and the movable seat 144 is fixed by an adhesive 150 (see for example, Japanese Patent Application Publication No. Hei 5-81693 pages 3 to 4, FIGS. 1 and 2).
As described above, in the conventional laser attachment device, the optical axis and the luminance distribution of the laser beam are adjusted by adjusting the position of the movable seat 144 for each of laser attachment devices after the optical axis adjustment mechanism part 142 is fixed to the base 141 of the laser attachment device. Accordingly, there are problems that the time required to attach and adjust the laser attachment device is difficult to reduce, working efficiency is poor, the laser attachment device is not suitable for mass production, and improvement in yield is difficult to achieve.
In addition, the adjustment of the laser beam requires fine movement of the movable seat 144 with respect to the fixed seat 143, and thus requires technique of a skilled worker. Accordingly, there is a problem of variation in adjustment accuracy depending on the skill of a worker.
The present invention is made in view of the above problems, and an object of the present invention is to provide a laser attachment device facilitating an adjustment work of a laser beam, and an optical pick-up device including the same.